Summary: In this paper the notion of interval-valued fuzzy KU-ideals (briefly i-v fuzzy KU-ideals) in KU-algebras is introduced. Several theorems are stated and proved. The image and inverse image of i-v fuzzy KU-ideals are defined, and how the homomorphic images and inverse images of i-v fuzzy KU-ideals become i-v fuzzy KU-ideals in KU-algebras is studied as well.